JP2001035046A - Tension detecting method of flexible tape and tension control thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To attain the precise tension control in accordance with the detection made by detecting the tension of a flexible tape without contact so as not affecting to the running condition. SOLUTION: The tape width of the flexible tape 1 is precisely detected without contact by tape width measuring devices 21, 22 such as a length measuring device utilizing a laser, and the tension value corresponding to the detected tape width is obtained in accordance with the correlation property between the preliminarily obtained tension value and the tape width. Also the tension of the running flexible tape 1 is controlled by the feedback control of this detected tension value or the detected tape width.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for detecting the tension of a flexible tape which can be detected in a non-contact state when the flexible tape such as a magnetic tape is wound up. The present invention relates to a method for controlling the tension of a flexible tape.

[0002]

2. Description of the Related Art Conventionally, when a relatively thin flexible tape, such as a magnetic tape, is run and winding is performed, detection of tension applied to the flexible tape in the running state and detection of the tension are performed. The control is necessary to perform stable running or uniform winding, and the tension is detected by various methods and the control is performed.

As a device requiring such tension control, for example, a so-called winder is widely known as a device for winding a magnetic tape around a reel in a cassette. In this winder, accurate tension control is required in order to ensure the flatness of the surface of the wound tape and the width of the wound tape, that is, the uniformity of the side surface of the wound tape. Also, VTRs and fixed head type magnetic tape recording / reproducing devices are widely used as data storage devices. In this data storage device, tension control is required to enhance the recording / reproducing characteristics.

[0004] In these devices, tension detection for tension control is generally based on fluctuations in mechanical parameters. That is, a pickup such as a guide is brought into contact with the running flexible tape, the tape tension is directly detected from the mechanical displacement, and this value is fed back to a motor or the like in real time to perform tension control.

[0005]

However, in the tension detection as described above, since the tension is detected by bringing the pickup into contact with the running flexible tape, the influence of this contact always exists. This affects the detection and the tension control of the traveling system, resulting in a decrease in accuracy.

Further, in order to increase the control accuracy of the tape tension, it is necessary to increase the accuracy of the tension detecting mechanism, and in order to obtain this accuracy, the measuring device becomes very complicated and expensive. In particular, there is a limit to the followability of the mechanical displacement of the pickup, and it is difficult to cope with an increase in the tape traveling speed.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems, and makes it possible to detect the tension of a flexible tape in a non-contact manner without affecting a running state, and to perform a highly accurate tension control. It is an object of the present invention to provide a flexible tape tension detecting method and a tension controlling method.

[0008]

According to the present invention, there is provided a method for detecting the tension of a flexible tape, comprising detecting a tape width of the flexible tape in a non-contact manner with high accuracy, and detecting a tension determined in advance. A tension value corresponding to the detected tape width is obtained based on a correlation characteristic between the value and the tape width.

Further, in the method of controlling the tension of a flexible tape according to the present invention, the tape width of the flexible tape is detected in a non-contact manner with high accuracy in a running state of the flexible tape, and is determined in advance. Based on the correlation property between the tension value and the tape width, a tension value corresponding to the detected tape width is obtained,
The tension of the flexible tape is controlled based on the tension value.

Still another method of controlling the tension of a flexible tape is to detect the tape width of the flexible tape in a non-contact manner with high accuracy while the flexible tape is running, and to set the detected tape width to a desired value. It is characterized in that the tension of the flexible tape is controlled so that the target tape width corresponds to the tension value.

In the present invention as described above, in the case of a thin and flexible flexible tape such as a magnetic tape, when the tape is pulled in a running direction at a certain tension, the tape width is determined by a so-called Poisson's ratio. Utilizes the property of shrinking from the tensionless state. The amount of change in the tape width has an accurate correlation characteristic with the applied tension. By accurately detecting the tape width in a non-contact manner with the flexible tape, the tape width is actually applied to the flexible tape. It is based on the basic principle that the tension that is applied can be detected in real time in a running state. Based on this, the tension control is performed by feeding back the detected tension value or the tape width.

As a premise of the above-mentioned principle, it is necessary that the absolute width of the flexible tape in a tensionless state is constant without changing at each portion in the longitudinal direction. That is,
The variation in the tape width is caused by the variation in the tension, and the variation in the tape width due to other causes must be negligible with respect to the variation caused by the variation in the tension.

In consideration of the above points, for example, when the flexible tape is a magnetic tape having a thickness of 10 μm and a tape width of 12.65 mm (reference value), the relationship between the tension and the tape width is an example. As shown in FIG. 3, the tension is 3
While changing from 0 g to 120 g, the tape width is about 2.2 μm.
m has changed. On the other hand, the normal winding length of this magnetic tape on a VTR cassette is about 500 m at the maximum, and the average fluctuation of the tape width (absolute width) at this 500 m length due to the performance of the cutting device is an actually measured value. 0.1 μm
Below, and the fluctuation occurs at a gentle slope,
This is the dimensional difference between the start and end of the tape. Therefore, the fluctuation amount of the tape width in manufacturing can be regarded as substantially constant and negligible for the tension detection and control in the continuous tape running, and the tape width corresponding to the tension fluctuation as described above is considered. It has been found that the tension detection and the tension control based on the fluctuation can be sufficiently used for practical use, and the necessary control accuracy can be secured.

Further, instead of measuring the tension of the flexible tape by a contact method, the width of the tape can be detected by a non-contact measuring device, and the tension value applied to the running flexible tape can be measured in real time. As a result, the influence of the contact on the tension detection and control can be eliminated, and the necessary tension detection accuracy and control accuracy can be ensured.
As the non-contact tape width measuring device, a laser length measuring device, a line CCD or the like can be used, and these measuring devices are known.

[0015]

According to the tension detecting method of the present invention as described above, the tape width of the flexible tape is detected with high accuracy in a non-contact manner, and the correlation characteristic between the previously determined tension value and the tape width is obtained. By obtaining the tension value corresponding to the detected tape width based on the above, it is possible to obtain the tension value in real time even in the tape running state without contact without installing the tension detecting means by the contact type pickup in the tape running system. Thus, accurate tension detection can be performed with little disturbance without affecting the running flexible tape.

Further, according to the tension control method of the present invention, the tape width of the running flexible tape is detected with high accuracy in a non-contact manner, and the running tape is detected based on the converted detected tension value or the detected tape width. By controlling the tension of the flexible tape, accurate and real-time tension control can be performed in a non-contact manner, and based on accurate tension control in winders and data storage devices, the flatness of the wound tape surface , Can ensure the uniformity of the tape winding width or good recording and playback characteristics,
It is also capable of responding to an increase in traveling speed.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail based on embodiments shown in the drawings. FIG. 1 shows a tape winding device provided with a tension detection method and a tension control method according to one embodiment of the present invention.

Tape winding device 10 (winder)
Is a method in which the flexible tape 1 (for example, 10000 m) wound on the material roll 11 is transferred to the cassette small reel 12 via a traveling system as a product having a predetermined length (for example, 500 m).
It is something to rewind. A plurality of guide rollers 1 for the traveling system
The flexible tape 1 runs along the guide roller 13. Further, a first capstan roller 15 is provided in the middle of the feeding side, and a second capstan roller 16 is provided in the middle of the winding side.
The running speed of the is adjusted.

A feed motor 1 is attached to the material roll 11.
7, the take-up motor 1 is mounted on the cassette small reel 12.
The motors 17 and 18 are connected to motor controllers 19 and 20 (control circuits) to control the driving.

The first capstan roller 15
A first tape width measuring device 21 is disposed on the upstream side as the first tension detecting unit 2, and a second tape width measuring unit is disposed on the downstream side of the second capstan roller 16 as the second tension detecting unit 3. A vessel 22 is provided. Each of the first and second tape width measuring devices 21 and 22 is constituted by a laser length measuring device.

As shown in FIG. 2, the tape width measuring devices 21 and 22 (laser length measuring devices) are substantially U-shaped as a whole, and the laser light emitting portions 23 are arranged on one side with the flexible tape 1 interposed therebetween. However, a light receiving unit 24 is provided on the opposite side, and extends in the width direction of the flexible tape 1 from the laser light emitting unit 23, and irradiates a linear laser beam L to the light receiving unit 24 in a range wider than the tape width. Since the laser beam L in the portion shielded by the flexible tape 1 is not received by the light receiving section 24, the width of the flexible tape 1 can be measured with high accuracy.

In the first tension detecting means 2, a detection signal from the first tape width measuring device 21 is sent to the motor controller 19 for the sending motor 17, and is converted into a tension value to detect the tension. In other words, in FIG.
Is converted into a tension value based on the characteristics of Then, the motor controller 19 compares the detected tension value with the set tension value, outputs a drive signal corresponding to the deviation to the delivery motor 17, and controls the tension on the delivery side.

Similarly, the second tension detecting means 3
In the above, the detection signal from the second tape width measuring device 22 is
, And is converted into a tension value in the same manner in light of the characteristics shown in FIG. 3 to detect the tension. The motor controller 20 compares the detected tension value with the set tension value, and outputs a drive signal corresponding to the deviation.
To control the tension on the winding side.

By averaging the tape width values obtained from the first and second tape width measuring devices 21 and 22 an appropriate number of times and eliminating small fluctuations due to disturbances, etc., a gentle tension control is possible. is there.

The flexible tape 1 is wound around the cassette small reel 12 with a predetermined tape tension by the above-described tension feedback control. As the winding tension control, there are a constant tension method of winding at a constant tension and a taper tension method of winding while gradually lowering the tension from the beginning of winding, and these are selected according to the characteristics of the magnetic recording / reproducing apparatus. Tension control is performed according to each request.
For example, in a broadcast VTR system, a flexible tape 1 of 500 m per roll (magnetic tape: 10 μm thick, tape width 1
(65 mm) is preferably wound by a constant tension method.

In the above-described embodiment, the tension is detected on both the sending side and the winding side of the flexible tape 1 and the feedback control is performed. Good. Further, in various devices using the flexible tape 1 other than the tape winding device 10, a tension is detected by measuring a tape width with respect to a running state of the flexible tape 1 to control the tape tension. It is good.

In the present invention as described above, the flexible tape 1
It is necessary that the tape itself has the flexibility that the tape width changes within a detectable range to some extent when tension is applied. It is necessary to provide a tape width measuring means capable of detecting the tape width. Further, for the flexible tape 1 to be measured, it is necessary to obtain a variation correlation characteristic of the tape width with respect to the variation of the tension in advance, and input this to the controllers 19 and 20. By these,
With the required precision, the tension of the flexible tape in the running state can be detected in real time from the detection of the tape width, and the feedback control of the tension using this can be performed with high precision.

In the tension control of the embodiment, the tension control is performed based on the detected tension value obtained by converting the tape width detected by the tension detecting means 2 and 3 into a tension value. The tension of the running flexible tape 1 may be controlled by the motor controllers 19 and 20 so that the tape width detected by the means 2 and 3 becomes a target tape width corresponding to a desired tension value.

[Brief description of the drawings]

FIG. 1 is a configuration diagram showing a flexible tape winding device provided with a tension detection method and a tension control method according to an embodiment of the present invention;

FIG. 2 is a schematic front view of the tape width measuring device of FIG.

FIG. 3 is a graph showing a correlation characteristic between a tension and a tape width of an example of a flexible tape.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Flexible tape 2, 3 Tension detecting means 10 Tape winding device 11 Raw material roll 12 Small reel 17 Feeding motor 18 Winding motor 19, 20 Motor controller 21, 22 Tape width measuring device 23 Laser light emitting part 24 Light receiving part L Laser light

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Akihiro Hashimoto 2-12-1, Ogimachi, Odawara-shi, Kanagawa F-term in Fuji Photo Film Co., Ltd. 5D037 AA11 AC11 BA05 BA18 CB02 FA05

Claims (3)

[Claims] 1. A tape width of a flexible tape is detected with high accuracy in a non-contact manner, and a tension value corresponding to the detected tape width is calculated based on a correlation characteristic between a tension value and the tape width determined in advance. A method for detecting the tension of a flexible tape. 2. In the running state of the flexible tape, the tape width of the flexible tape is detected with high accuracy in a non-contact manner, and based on a correlation characteristic between the tension value and the tape width determined in advance, the tape width is determined. A tension control method for a flexible tape, comprising: obtaining a tension value corresponding to a detection tape width; and controlling the tension of the flexible tape based on the tension value. 3. In a running state of the flexible tape, the tape width of the flexible tape is detected in a non-contact manner with high accuracy, and the detected tape width becomes a target tape width corresponding to a desired tension value. And controlling the tension of the flexible tape.